Way to go bumping this thread back up for spring 2003 :-) Everyone has done a great job covering the bases. How about adding:
(1) Carry your pesticide and business license in your vehicle in case you are questioned;
(2) Carry your insurance information in the vehicle in case there's an accident;
(3) Release pressure on your pesticide sprayer tank after you finish the application just in case somebody bumps it by accident; that way they don't get hosed down and blinded;
(4) Always walk a site before beginning work and take note of hazards and/or already damaged property to reduce problems.